Method of rolling



pt. 1940- A. B. MONTGOMERY METHOD OF ROLLING Filed Oct. 23, 1936 6 Sheets-Sheet l INVENTOR 14L 0/720 fi/flomyamery w M /W Sept. 10, 1 A. B. MONTGOMERY METHOD OF ROLLING Filed Oct. 23, 1936 6 Sheets-Sheet 2 M m wN wNw m, fir .JN WM. m H l N I Z 4 l m 2 I W W II fl l l M QM- QN. 1||| QN M MN MN QM QM N mm. I N 0 NM. m NM 5 I N Sept. 1940- A. s. MONTGOMERY 2,214,107

ammo 0F ROLLING Filed Oct. 2a. 1956 s Sheets-Sheet} NNN Sept. 10, 1940.

A. B. MONTGOM ERY METHOD 0F ROLLING Filed Oct. 23, 1956 6 Sheets-Sheet 4 ill 3 [III mm QQNI mm -HHHHH. QQN. S

INVENTOR 440/120 fiMomgomery wwwzm S pt 10, 1940- A. B. MONTGOMERY 2,214,107

METHOD -OF ROLLING Filed Oct. as. 1936 s Sheets-Sheet 5 I INVENTOR ALonzo fiMonzgo/nery' m MZM Sept. 10,1940. MONTGOMERY I 2,214,107

METHOD OF ROLLING Filed 001;. 23, 1936 6 Sheets-Sheet 6 INVENTOR Aumzo 5 Monzgomery J25 WWI QM Patented Sept. 10, 1940 PATENT OFFICE 2,214,107 METHOD OF ROLLING Alonzo B. Montgomery, Youngstown, Ohio, as-

signor to The Cold Metal Process Company, Youngstown, Ohio, a corporation of Ohio Application October 23, 1936, SerialNo. 107,193

10 Claims.

This invention relate: to the rolling of metal and particularly to the hot rolling of strip. The hot rolling of strip, by passing a breakdown repeatedly back and forth through a single-stand mill, has been contemplated for many years. It is only recently, however, that any progress has been made in applying this idea in actual practice.

When it was first attempted to roll strip in a 10, single-stand mill with coiling furnaces on both sides thereon, the unwinding reel was retarded to prevent over-running thereof. The principal difllculty with early single-stand strip mills, however, was that they were incapable of consistently 15 rolling a breakdown without camber or longitudinal curvature. This made it necessary to permit the breakdown to coil as it would, loosely, on the winding reel. Because of the looseness of the coil on the winding reel, skidding or axial o shifting of the turns on the coil being wound up occurred with the result that on the next pass, the back tension imparted to the breakdown by the retarding of the unwinding reel caused one edge or the other to strike the side guides which 25 were employed. This caused the edge of the strip to be folded over into a double thickness.

In my co-pending Patent 2,072,121, for Method and apparatus for guiding material, I have described and claimed a method and apparatus for 30 guiding a slab and the breakdown rolled therefrom so that the latter, when finished, is free from camber. The present invention is useful particularly in conjunction with that of the application aforementioned.

5 In my copending Patent 2,072,122, I have described and claimed a mill which is an improvement over those of the types shown in United States patents to Keeney et al. No. 1,918,968 and Steckel No. 1,977,214, including guideson both 40 sides of the mill which, while operating on the principle described and claimed in the first mentioned copending application represent a structural improvement over the latter. Beyond the guides, pinch-rolls are disposed and coiling reels 45 are mounted within heating furnaces, in the general manner shown in'the patents referred to. In accordance with the present invention, however, I utilize the pinch-rolls only while starting the leading end of a breakdown through the mill 5 and into the coiling reel on the opposite side, the pinch-rolls being thereafter retracted, freeing the strip between the mill and the reel. I then apply sufficient torque to the shaft of the winding reel to tension the portion of the breakdown be- 55 tween the reel and the mill. I also apply a back tension to the portion of the breakdown between the mill and the unwinding reel thereby exerting a retarding torque on the shaft of the latter. By thus tensioning the breakdown, I am able to form a tight coil on the winding reel, thus eliminating skidding and preventing camberingl of the product during the later rolling passes.

The guides on the exit side of the mill prevent cambering of the leading end of the breakdown until the latter is engaged by the pinch-rolls. The pinch-rolls prevent cambering of the end until the latter is engaged by the coiling reel. With the accurate start thus obtained, correct coiling of the breakdown is assured when the pinch-rolls have been retracted and the guides have ceased to have any effect because of the engagement of the end by the reel. The guides will, however, correct any incipient camber which may appear before the leading end has entered the pinchrolls. The forward tension, furthermore, will pull out any camber which the mill tends to produce in the breakdown, after the latter has been started on the reel; and the same is true of any camber produced between the pinch-rolls and the reel. So long as the breakdown is free between the mill and coiling reel, it may be controlled by the side guides.

I drive the coiling reel so that at the point where the breakdown enters the reel is moving in a direction opposite that of the strip.

The method of my invention may be best explained by describing a preferred form of the apparatus for carrying it out. This apparatus which is also described and claimed in my Patent 2,072,122, is shown in detail in the accompanying drawings. In the drawings:

Figure 1 is a horizontal section through a mill having my invention incorporated therein showing parts in plan;

Figure 1A is a. partial, sectional view similar to Figure 1 showing a slightly modified form of construction;

Figure 2 is a partial side elevation with the mill housings removed for the sake of clearness;

Figure 3 is a partial sectional view along the line III-III of Figure 2, showing parts in elevation;

Figure 4 is a partial, vertical section through the coiling furnace showing other parts in elevation to a slightly enlarged scale;

Figure 5 is a side elevation similar to Figure 4 showing a modified form of construction embodying pinch-rolls particularly adapted for automatic operation, as well as flattening rolls;

Figure 6 is a vertical, sectional view along the line VIVI of Figure 5 showing parts in elevation;

Figure 7 is a partial, sectional view along the line VII-VH of Figure 5;

Figure 8 is a schematic diagram of the automatic control system for the apparatus of Figures 5 through 7;

Figure 9 is a similar view of the system for controlling the guides of Figuresl through 3;

Figure 10 is a diagrammatic plan view of the mill and the driving motors therefor; and

Figure 11 is a side elevation corresponding to Figure 10.

Referring in detail to the drawings, a mill It) comprises housings ll having windows l2 for receiving bearing chucks adjustably positioned therein. Backing rolls l4 and working rolls [5 are journaled in the'chucks, the rolls preferably having anti-friction bearings, not shown. The housings l I are connected by transoms l6.

Auxiliary housings l8 are positioned on opposite sides of the mill. Roll tables l9 extend between the housings l8 for conveying material to and from the mill rolls. Furnaces 20 having coilers 2| therein are positioned at a convenient distance from the mill. Tilting guides 22 are provided on the roll tables I9 for diverting material aduancing through the mill from a horizontal path of travel into the coilers 2 I. These coilers are simply spools of convenient size with suitable driving and control equipment, each spool having blades 23 positioned therein, as shown in Figure 4, so that when the leading end of the strip enters one of the coilers between adjacent blades 23, the rotation of the coiler bends the strip around the leading edge of one of the blades. The remainder of the strip is then drawn around a scale-breaking roll 24 at the edge of the furnace mouth and wound up on the coiler.

The rolls 24 are driven by motors 24a (Fig. 10) the direction of rotation of the rolls being such as to aid movement of the breakdown toward the reel. This eliminates any drag on.the breakdown which might tend to prevent a positive engagement with the reel. As shown in Fig. 4, the coiling reel is driven in a direction such that the blades on the lower side move in a direction opposite that in which the strip moves.

A base 25 is carried between each of the auxiliary housings I 8. Bottom guides 25 are pivotally supported on the bases 25 at 21. The guides 26 are also supported by flat seats 28.

Top guides 29 arepivotedat 30 to the transoms l6 and are suspended from angle bars 3|| extending across the mill between the chucks l3 for the top backing rolls, by links 32. The inner ends of the guides 26 and 29 are shaped to conform closely to and are actually in contact with the work rolls to effect a stripping action in case the piece tends to follow aroundthe periphery of one or the other of the rolls.

In the subsequent description of the invention, I shall refer specifically to the equipment on the right-hand side of the mill only, as shown in Figures 1, 2 and 4, but it will be understood that duplicate equipment is employed on the opposite side of themill.

Screw shafts 33 are slidably' mounted in the housing l8'parallel to the axes of the mill rolls. Side guides 34 are supported on the screw shafts 33 by hinged joints 35. The guides 34 have a plane inner surface 36 with recesses into which anti-friction rolls 3! are let. The mill ends of the guides extend to a point closely adjacent the rolls, as shown in Figures 1 and 2. The outer ends of the guides are pivotally supported on nuts 38 traveling on a screw shaft 39 journaled in the side frames of the table IS. The ends of the screw shaft 39 are oppositely threaded so that on rotation of the shaft, the outer ends of the guides are moved toward or away from the center line of the table [9.

From what has been said, it will be apparent that my invention provides side guides which may be disposed in parallel relation, as shown on the left-hand side of the mill in Figure 1, or in angular relation, as shown on the right-hand side of the mill in Figure 1, for the purposes, re-

spectively, of definitely and positively guiding the leading end of an advancing strip into the rolls at the proper angle thereto, and providing a tapering throat for receiving the end of the piece as it emerges from the mill. I shall now describe the mechanism for operating the guide supports to bring about the proper relation 0 the guides at the proper time.

The outer ends of the guides may be adjusted toward or away from each other through the shaft 39, as already described. This adjustment is effected by a hand wheel 49 having a pinion 4| meshing with a gear 42 along the screw shaft 39. A suitable pedestal bearing 43 is provided for the hand wheel shaft 44. The outer ends of the guides 34 are adjusted manually to the proper spacing before commencing the rolling.

The adjustment of the inner ends of the guides 34 is effected through the screw shafts 33. Gear cases 45 attached to the housings l8 enclose gear wheels 46 having their bores threaded for engagement with the shafts 33, and pinions 41 keyed to shafts 48. Hand wheels 49 permit manual adjustment of the screw shafts 33. These shafts are normally driven from extensions 50 of the shaft of one of the rolls 5| of the table IS. The rolls of the table are driven from a line shaft 52 through the usual bevel gears by a reversing motor, not shown. Between the shaft extensions 50 and the shafts 48 are positioned friction clutches 53 and jaw clutches 54 having operating levers 55. The purpose of the friction clutches is to permit the rotation of the shaft 48 to be arrested after a predetermined movement thereof without stopping the operation of the roll 5!. The jaw clutches 54 permit the shafts 33 to be freed from the table drive while being manually adjusted.

The friction clutches 53 have detents 56 thereon cooperating with stops 51 on the housings l8 to limit rotation of the shaft 48 to the desired extent. After the detents engage the stops, the adjustment of the shafts 33 ceases but the roll 5| continues rotating with accompanying slippage of the clutches 53.

It will now be apparent that once the outer ends of the guides 34 have been adjusted, the inner ends of theguides will be spread to form a tapering throat or moved together to parallel position with the reversal of the drive for the rolls of table I9. The detents and stops controlling the amount of rotation of the friction clutches will determine the amount of movement imparted to the inner ends of the guides and may, if desired, be made adjustable. It will be understood, of course, that the guide-operating mechanism is designed so that the guides will be spread at the mill end when the table rolls are driven in such a direction as to move material away from the mill. At the same time, the guides on the opposite side of the mill will be actuated to parallel position. In this way, the material advancing toward the mill is definitely and positively alined at right angles to the plane containing the axes of the mill rolls. The emerging material is in no wise obstructed but is gently received within a slightly tapering guiding throat. In both cases, the anti-friction rolls 3'I prevent binding and insure continuous, steady forward movement of the material without grabbing or slipping. As before stated, the extreme posi tions of theinner ends of the guides may be ad- Justed initially by hand after disengaging the clutches 54. Thereafter, the range of movement of the inner ends of the guides is determined by the location of the detents 58 and stops 51. In

the construction illustrated, I have assumed that one complete revolution of the shaft will produce the necessary movement of the inner ends of the guides.

Referring now particularly to Figure 4 for a disclosure of the flattening rolls, housings 88 supported on side members of the roll table I9 have bearing chucks 6| movable vertically therein by means of a pneumatic cylinder 82. Rolls 83 and 84 journaled in the chucks 8| cooperate with adjacent rolls of the table l9. A roll 86 also journaled in the chuck 8| cooperates with a roll 81 journaled in adjustable chucks 88. The chucks 88 are actuated by pneumatic cylinders 89.

The rolls 83 and may be driven and when' the former is lowered into engagement with the latter, they serve as pinch rolls to feed the strip toward the mill from thecoiler 2|. When the strip has been started through the mill and engaged the coiler on the opposite side thereof, the chucks 8| are preferably raised and the rolls 63, 94 and 68 lifted off the strip. The chucks 88 of the rolls 8'! are preferably lifted at the same time as the chucks 6|. In its normal lower position, however, the roll 81 is effective to assist in flattening or leveling the leading end of the material in its passage from the mill to the coiler. The pinch rolls 63 are lowered, of course, at this time. If the leading end, after passing through the pinch rolls, is deflected downward, it will engage the roll 61 and then the roll 85. On passing between the rolls 64 and 65, the end will be flattened sufficiently to engage the coiler 2| without difllculty. Similar results occur if the lead ing end of the piece is deflected upward, in which case it wil engage the rolls 68 and 84 successively, and after passing between the roll 84 and the. roll 85 cooperating therewith, will be found to be satisfactorily flattened. The control of the fluid supplied to the cylinders-82 and 69 has not been illustrated since it may be of any desired character, automatic or manual.

Figure lA'illustrates a modified form of actuating mechanism for the guides 38. This means takes the form of pistons 10 reciprocable in cylinders II by means of fluid pressure, hydraulic or pneumatic, supplied thereto. The pistons 18 have piston rods 12 attached thereto corresponding to the screw shafts 33 and functioning in the same way, under the influence of fluid pressure admitted to either side of the cylinders 1| for actuating the guides.

A modified form of construction of the auxiliary rolls for feeding and flattening the strip is shown in Figures 5 through 7. A roll table 13 has side frame castings 14. Housings 15 are attached to the castings l4 and have windows 16 therein in which bearing chucks 11 are slidable. Cylinders 18 formed in the upper part of the housings 15 have pistons 19 reciprocating therein. Piston rods 88 attached to the pistons 18 are threaded into the chucks 11 whereby the latter may be lifted to the dotted line position shown in Figure 5. Piston rods extend outwardly through the upper end of the cylinders 18 and are connected by cross beams 8|. Cylinders 82 carried on a transom 83 extending between the housings, also have pistons and piston rods arranged as shown in Figure 6 whereby the beams 8| and, therefore, the chucks 11, may be raised through a small distance. The piston rods of the cylinders 82 have separable, abutting engagement with bolts 8|a. It will be apparent that the cylinders 19 and 82 provide independent means for lifting the chucks 11 through a long stroke and a short stroke, respectively. The object of this arrangement will become apparent as the description proceeds.

An equalizing shaft 84 extends between the housings l5 and is journaled therein. Cranks 85 keyed to the shaft 84 carry trunnions 88 in slidable bearing blocks 81. The trunnions 88 are threaded into the chucks ll, as best shown in Figure 6. The equalizing shaft obviously serves to effect simultaneous and equal movement of both bearing chucks and prevents binding of the reciprocating mechanism.

A top pinch roll 88 is journaled in the chucks H for cooperation with a bottom pinch roll 89,

which may conveniently be one of the rollers of the table 13. Flattening rolls 90 and 9| are also journaled in the chucks 11. The roll 9| cooperates with a roll of the table 13. A roll 92 is journalled in chucks 93- slidable vertically in the base portions of the housings 15. Cylinders and pistons 94, bell crank linkage 95 and struts 96 are provided, as shown in Figure 5 to effect vertical movement of the chucks 93 for a purpose which will appear later.

As best shown in Figure 7, the roll 99 is journaled in chucks 91 secured to the chucks I1. -A contact-actuating rod 98 is threaded into a projection 99 from one of the chucks 93. The rod 98 also passes through guides I98 projecting from one of the chucks 91. The rod 98 controls the engagement of a moving contact l8| with a fixed contact I 82 on one of the chucks H for a purpose which will presently appear.

The chucks 93 are normally lowered so that contact lill engages contact I82. These contacts control a circuit for stopping the main mill motor in case of breakage of the strip. When the strip is being rolled, the rolls 88, 98 and 9| rest on the strip and are spaced thereby from the rolls 89 and 92. After the strip has been entered into the mill so as to separate the pinch rolls 88 and 89, fluid is admitted to the cylinders 94 to cause the chucks 93 to be raised until the roll 92 engages the lower surface of the strip. The rolling operation then proceeds. If breakage of the strip should occur, the continuing fluid pressure in the cylinders 94 causes the chucks 93 to rise until the roll 92 actually engages the roll 90. This causes the rod 98 to move upwardly and lift contact Hll out of engagement with.contact I82. Separation of these contacts, through suitable auxiliary equipment, causes stoppage of the main mill motor.

The cylinders 19 and 82 are automatically controlled to cause the pinch rolls 88 and 89 to engage the material at certain times andto release it at other times.

In rolling a slab into strip on the mill "I, it is desirable that the pinch rolls 88 be withdrawn as long as the slab being reduced has sufficient rigidity to permit it to be fed back and forth to and from the mill by the friction of the table rolls. when the slab has been reduced to a gauge such that it has relatively little rigidity, or to a condition in which coiling between passes is advisable, the pinch rolls are advanced to assist in threading the strip through the mill at the beginning of each pass. While both ends of the strip actually pass through the mill, the pinch roll motors are so controlled that neither end of the strip is disengaged from the pinch rolls on both sides of the mill. At least one end of the strip is always engaged by at least one set of pinch rolls. It is by these pinch rolls that the strip is then fed back to the mill for the next pass. On the exit side of the mill, the pinch rolls assist in delivering the leading end of the passing through the mill;

' strip into the coiler by pushing it up the guide The system for automatically controlling the pinch rolls will be now explained with reference t8 Figure 8. In Figure 8, the work rolls of the mill are indicated by the same numeral as in Figures 1 and 2. A motor I03 is provided for driving the mill and the power of the motor may be applied directly to the work rolls I5 or to the backing rolls I4. The motor I03 may be controlled by any suitable control system. For simplicity, I have only illustrated a control panel I04 having incoming power leads, outgoing motor leads, and outgoing control leads extending to a controller I05. The panel I04, of course, will be provided with suitable relays and contactors efiective under the control of the controller I05 to cause starting of the'motor I08. The panel I04 also has a relay I08 effective when deenergized to cause stopping of the motor. The specifio details of such an arrangement are known and need notbe included here. The controller I05, obviously, is effective on being shifted manually in one direction or the other, to cause operation of the motor I03 to drive the mill rolls I5 and thus move the strip through the mill in the desired direction. The supply of fluid to the cylinders I8, 82 and 94 is controlled by a master valve I01 and auxiliary valves I 08 and I09. The valve I0'I has operating magnets H0 and III and the valve is of such character that it remains in the position to which it was last operated until positively actuated therefrom. The valves I08 and I09 have operating magnets H2 and H3. The arrangement of these valves and their operating magnets is such that they remain in the illustrated position until the magnets areenergized, and return to the illustrated position when the magnets are deenergized.

The valve I01 is controlled by a limit switch II4 operated by any convenient means, in accordance with the position of the mill screwdowns which determine the thickness of the pass between the rolls and the material itself after When the space between the mill rolls I5 is greater than a predetermined value, say A,", the limit switch II4 closes its lower contacts to energize the magnet III and move the valve I0I so that fluid under pressure is supplied from a reservoir I I 5 through suitable piping, to the cylinders 18 on both sides of the mill. The pistons I9 are thereby actuated full stroke to withdraw the upper pinch -roll 88 and provide ample free space for the passage back and forth to and from the mill of the slab in the initial stages of its reduction to strip.

When the thickness of the slab has been reduced to a point such that, on the next pass,

the mill rolls are spaced apart only or less, the partially reduced material is suiilclently thinned and elongated to permit of coiling and, at the same time, its rigidity is such that the assistance of the pinch rolls is required to manipulate it through the mill and into the coilers. The limit switch II4 then closes its upper contacts to energize the magnet H0 and operate the valve I01 to the illustrated position. This vents the cylinder I8 and the pistons I9 immediately drop to lower the pinch rolls 88 onto the material. The pinch rolls are driven by any convenient means, at the same peripheral speed as the rolls I8, so as to cooperate therewith in moving the material back and forth.

If it is assumed for the sake of explanation that the breakdown formed from flat rolling the slab was reduced on a p from left to right, to a gauge such that after the next reduction, it would be less than thick, as soon as the top roll I5 is lowered to within less than 5 of the bottom roll, the described operation of the valve I01, will take place and the pinch rolls will seize the breakdown for the next pass from right to left. When all is ready for this pass, the roller operates the handle of the controller I05 to the left, as shown in Figure 8, whereupon the motor I03 is operated so as to drive the rolls II and roll the strip from right to left. The pinch roll drive is so coordinated with that of the mill that the pinch rolls 88 are simultaneously operated so as to assist in the feeding of the breakdown.

The movement of the controller I 05 bridges contacts II8 to energize a relay I IT. The relay II! has a time delay in its operation, indicated by a dashpot, and after a certain time bridges contacts IIIa to energize the magnet H3. The relay is adjusted so that the contacts I IIa will be bridged just after the leading end of the breakdown being rolled passes between the rolls I5. The magnet II3 operates the valve I09 to admit fluid supplied through the valve I0'I to the cylinders 82 on the entering side of the mill. The pinch roll 88 on that side is thus lifted from the material.

After a slightly longer time, the relay I I1 operates to bridge its contacts IIIb, maintaining the circuit for the magnet II3 by reason of the fact that the bridging contact slides along the contacts I I'Ia. The relay is adjusted so that the contacts II'Ib are bridged after the material has emerged from the millon the exit side, passed through the pinch rolls, and made one turn about the coiler. The bridging of the contacts IIIb causes the operation of magnet 2 to shift the valve I08. The cylinders 82 on the exit side of the mill thus operate to raise the associated pinch roll from the strip. The strip is thus free between the winding and unwinding coilers, except where engaged by the mill.

The operation of the valves I09 and I08 describd above, also causes the operation of the cylinders 94 on opposite sides of the mill. The roll 92 is thus raised into engagement with the material but is sufliciently spaced thereby from the roll that the contact I 0| remains in engagement with the contact I02. sure is continuously applied to the cylinders 94 as long as the rolling continues but, unless the strip breaks during rolling, the rolls 90 and 92 are maintained separated and the contacts IN and I02 remain in engagement. If the strip is broken, the roll 92 is immediately lifted into engagement with the roll 90, whereupon the rod 98 lifts the contact IOI to open the circuit for the relay I06 and thereby stop the motor I03.

As soon as the leading end of the breakdown has been engaged by the coiling reel, and the pinch rolls retracted,1 cause the motor12Ia driving the coiling reel to exert thereon a torque sufficient to impart tension to the breakdown between the coiling reel and the mill. At the same time, I operate the motor 2Iaconnected to the unwinding reel as a generator, to impart a back tension to the portion of the breakdown between the uncoiling reel and the mill. exerted by the motor and generator are preferably maintained constant by any convenient means such as current regulators effective to maintain constant currentsthrou'gh the arma tures of the motor and generator. The relationship of the regulators to the motor and generator is reversed on reversal of the mill, the regulator for the coiling-reel motor, obviously, being set for agreater current than the regulator connected to the uncoiling-reel generator.

By this provision, I tension the breakdown on the exit side of the mill between the mill and coiling-reel. On the entrance side, the breakdown is tensioned between the mill and the uncoiling-reel. I

When the pass is completed, the controller I is restored to neutral position so that the trailing end of the strip stops between the mill and the pinch rolls on the exit side thereof. The relay H1 is thus deenergized and substantially immediately opens its contacts to deenergize magnets H2 and H3. The cylinders 82 are thus exhausted to the atmosphere and the pinch rolls dropped. At the same time, the cylinders 94 are exhausted through check valves H8, the weight of the roll 92 and chucks 93 serving to force the accumulated fluid out of the cylinders. The operating fluid for the cylinders 94 passes initially through expansion valves H9 which slightly delays the lifting of the chucks 93 on starting a pass.

The next pass is accomplished in exactly the same manner. Reversal of the controller I05 energizes the relay I20 and this, in turn, causes sequential lifting of the pinch rolls 88 on the entering and exit sides of the mill. This cycle is repeated until the strip has been reduced to the desired gauge, when it is wound on a coiler beyond the furnace on the exit side of the mill. The top work roll is then lifted by reversal of the screwdowns. The switch H4 closes its lower contacts and operates the valve I01 to admit fluid under pressure again to the cylinders I8, whereby the pinch rolls 88 on both sides of the mill are lifted out of the way for the next flat rolling operation.

Figure 9 shows how the side guide actuators of Figure 1A are controlled. When the controller I05 is shifted so as to cause the material to be fed from left to right, it closes contacts I2I. It will be understood that operation of the controller also, through appropriate relays, causes the starting of the motor I03 in the proper direction. The closing of the contacts I2I energizes an operating magnet I22 for a valve I23. This valve is similar to that shown at I01 of Figure 8. The energization of the magnet I22 operates the valve to the position illustrated in 3 Figure 9, in which it delivers fluid under pressure to the inner ends of the cylinders H on the exit (left-hand) side of the mill, and to the outer ends of the cylinders on the entering (righthand) side of the mill. The guides 36 on the entering side are thus closed in, as indicated in The torques Figure 9, while the guides on the exit side are opened to permit free passage of thematerial as it emerges from the mill.

On the reversal of the direction of rolling, for the next pass, the controller I05 bridges contacts I24 and energizes a magnet I25 to shift the valve I23 to the other position. The reverse operation of the cylinder 'II then takes place to close the guides on the left-hand side and open the guides on the right-hand side.

It will be understood that only a single controller =I05 is employed and that it controls contacts' I I6 and I24, f J1 example, simultaneously, in addition to the other contacts necessary to bring the motor I03 up to operating speed. The sys-' tem of Figure 9 is shown separately from that of Figure 8 simply because it is a diagrammatic plan, whereas the latter isa diagrammatic elevation, but it will be understood that the two systems are combined and under the common control of the controller I05.

It will be apparent from the foregoing description that my invention provides a rolling mill having numerous advantages over known apparatus of the same kind. In the first place, the slab or strip is definitely guided into the mill along the pass line or longitudinal axis of the mill. There is thus no possibility for the strip to move into the rolls crabwise at a slight angle to the pass line. Cambering of the strip or slab is thus prevented. Free' movement of the highly flexible, thin strip from the mill is permitted without obstruction since the guides on the exit side of the mill are automatically retracted to form a tapering guiding throat. The positions of the guides on opposite sides of the mill are reversed automatically with the reversal of the roll tables and the mill so that once the guides have been adjusted, they require no further attention until a different width of material has to be rolled.

The flattening rolls insure that the leading end of the strip will always be sufficiently flat to enter and engage the coiler properly to wind the strip thereon. This avoids the delays experienced heretofore incident to the backing up of the strip and repeating the entry thereof into the coiler after a first unsuccessful attempt.

The top and bottom guides 29 and 26 respectively, with theside guides 34, form a complete guide box and prevent any departurev of the strip from the pass level or the horizontal plane through the roll pass. With the guides of my invention, improper entry of the material into the mill is rendered almost impossible. The top guide may be adjusted by a turn-buckle in the links 32. The bottom guide may besimilarly adjusted by shimming up the outer end thereof which rests on the seat 28.

The automatic control of the pinch rolls on both sides of. the mill insures that the strip will be advanced properly into the mill and, on emerging therefrom, into the coiler, whereupon the pinch rolls will be lifted out of the way when there is no further need for them. The automatic stop mechanism prevents loss, damage or injury in case the strip breaks during a pass.

The positive actuation of the side guides under the control of the main controller causes the strip to be properly started toward the mill and correctly positioned with respect thereto before it actually enters between the mill rolls, after which no effort is sufiicient to correct an improper starting of the strip, because of the great force exerted on the strip by the rolls.

The top guide 20 has an important function in preventing the ceiling up of the leading the piece when rolling in the flat. If it were not for this guide, the slab, in the early stages of its reduction, might bend up sumciently to escape the side guides altogether, whereupon it might be improperly entered into the mill pass on the next reversal.

By tensioning the portion of the breakdown between the mill and the coiling reel, I cause the material to coil tightly and accurately on the coiling reel, thus avoiding skidding and possible deformation of the edge of the breakdown on the next pass. The tension also serves to remove any camber which might be rolled into the strip by the mill. By raising the pinch rolls after starting the piece through the mill, I avoid introducing camber into the material as a result of the reduction caused by the pinch rolls. The guides serve to correct camber of the leading end of the piece while it is free. The pinch rolls tend to prevent the introduction of the camber before the piece is started on the reel. Thereafter, the forward tension prevents cambering at a time when the guides are comparatively inefl'ective. If the material departs from the center line of the mill while the pinch rolls engage it, this departure will be corrected as soon as the pinch rolls are raised and forward tension is applied.

By driving the coiling reel in a direction such that the point where it is engaged by the leading end of the breakdown is traveling in a direction opposite that of the latter, I ensure positive engagement by hooking the end of the piece around the leading edge of one of the reel plates.

Although I have illustrated and described only one embodiment of my invention, it will be apparent that numerous changes therein maybe made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. In a method of hot rolling a breakdown into strip by passing it back and forth through a mill having pinch rolls on both sides-thereof and coiling reels beyond the pinch rolls, the steps including causing the pinch rolls on one side of the mill to engage the trailing end of a breakdown coiled on the reel on thatside of the mill, driving last mentioned pinch rolls to feed said end back to the mill, driving the pinch rolls on the other side while maintaining them in gripping engagement with the breakdown to feed said end toward the other reel, and retracting at least one of each set of pinch rolls to free the breakdown between the mill and the reels during the remainder of the pass.

, 2. The method defined by claim 1 characterized by so driving the winding reel as to tension that portion of the breakdown bet-ween it and the mill. h

3. The method defined by claim 1 characterized by so retarding the unwinding reel as to ten sion that portion of the breakdown between it and the mill.

endof 4.1namethodofconvertingaslab oringot into strip, the steps including passing a slab back and forth in the flat between reducing rolls to form a breakdown, passing the breakdown back and forth between reducing rolls to form a strip, winding the breakdown on a coiling reel between passes through the rolls, bending the breakdown about a guide roll, and driving said guide roll to prevent frictional drag on the breakdown.

5. The method defined by claim 1 characterized by retracting one of each set of pinch rolls a greater distance before starting the rolling of a breakdown-into a strip, while rolling the breakdown from a slab or ingot without coiling.

6. In a method of rolling strip, the steps including passing a breakdown, heated to plastic condition, back and. forth between reducing rolls, uncoiling it on one side and coiling it on the opposite side of the rolls, passing an end of the breakdown entirely through the rolls, frictionally gripping said end to feed it back through the rolls, freeing that portion of the breakdown between the mill and the point of boiling, and tensioning such portion uniformly throughout.

'1. In a method of. making strip by passing a breakdown, heated to plastic condition, through reducing rolls, coiling the strip on the exit side, uncoiling it from a previously formed coil on the entrance side of the rolls, gripping the strip at points between the rolls and points of coiling only long enough at the beginning of each pass to thread the end of the breakdown through the rolls and start coiling thereof on the exit side, and then freeing the breakdown between the rolls and the points of coiling, while continuing to pass the strip through the mill in the same direction.

8. The method defined by claim'l characterized by tensioning the portion of the breakdown between the rolls and the point of coiling uniformly throughout to cause the breakdown to coil straight and true.

9. In a method of rolling strip, the steps including passing a breakdown back and forth between reducing rolls, coiling the breakdown on one side of the mill between passes, frictionally engaging the outer end of the coil to drive it back toward the mill between parallel edge guides, receiving said end as it emerges from the mill between converging edge guides, frictionally engaging said end to drive it toward the point of coiling on the exit side of the mill, and freeing the portions of the breakdown inwardly of the edges thereof and between the mill and the points of coiling from frictional driving or retarding engagement.

10. The method defined by claim 9 characterized by coiling the breakdown emerging from the mill under torque sufficient to tension uniformly that portion of the breakdown between the mill and point of coiling to cause it to wrap true in a: 0011. Q

ALONZO B. MONTGOMERY. 

